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Brewing Topics => Brewing Discussion => Topic started by: Exit12Brewery_Nick on October 21, 2019, 06:36:09 AM

Title: BH & Mash Efficiency: Not Consistent & Not Good - WHY?!
Post by: Exit12Brewery_Nick on October 21, 2019, 06:36:09 AM

Hey all! I've had BeerSmith V3 and the Robobrew V3 for about a year or so. Unfortunately in that time I've had issues not only with getting high Mash & Brewhouse Efficency, but MAINTAINING consistency whatsoever and I'm not sure why. In the research I've done, I've looked at some of the bigger reasons why that might be:

Grain Crush: We use a MaltMuncher Pro w/ credit card thickness on the mill & have used another mill previously. Same result.

qt/lb ratio: It has ranged from 1.7-1.25, some recipes with 50/50 mash-sparge water ratio.

Water Chemistry: We utilize chemicals for all of our beers based on specific style guidelines.

Stir The Mash: We just started stirring the mash and have seen a minor uptick in mash efficiency, not BH.

My cousin & I are at a complete loss on what the issue(s) could be. We have a Cranberry Pale Ale brew day coming up. This is our 2nd year in a row brewing it for Thanksgiving. Here are the numbers we got the first time we made it, with the Robobrew V3 that we'll be using again:

Hazy Cranberry Pale Ale:

- 78.5% BH Efficiency

- 1.7 qt/lb ratio

We've been focusing more on efficiency as of late, and recently brewed a New England IPA in the Robobrew, with the following results:

- 61.9% BH Efficiency

- 1.321 qt/lb ratio

- 72% mash efficiency

My concern is we're adding about 1.5lb more flaked adjuncts in this years Cranberry Pale Ale than in last, so I assume those efficiency numbers will take a dip.

How do you maintain a consistent efficiency on an all in one system like the Robobrew utilizing software like BS3?

Thanks for the help. Cheers!
Title: Re: BH & Mash Efficiency: Not Consistent & Not Good - WHY?!
Post by: brewfun on October 21, 2019, 07:47:35 AM
Brewhouse efficiency (BHE) equals mash efficiency multiplied by the percentage of wort that makes it to the fermenter. In other words, BHE is the percentage of total sugars available that make it to your fermenter.

If you have a 6 gallon batch size (in the fermenter) and a half gallon of trub, then you have 92.3% of what's in the kettle making it to the fermenter. You gave us 72% mash efficiency.

0.72 x 0.923 = 0.665 (66.5%) BHE.

The rest of the factors you provided can be good for increasing mash efficiency, but won't change how much trub is left in the kettle. I doubt a half pound change in flaked grains will make a difference. What matters in your liquor to grist weight is enzyme contact with substrate. Too thick and you don't get enough solubility, too thin and the substrate gets too diffuse. Luckily, barley wants to become beer, so anywhere between 1 to 2 quarts/lb is just fine for conversion if the pH is right.

Title: Re: BH & Mash Efficiency: Not Consistent & Not Good - WHY?!
Post by: Exit12Brewery_Nick on October 21, 2019, 07:50:56 AM
Thanks for the info. 66.5% BHE isn't accurate, according to the BeerSmith calculator though. They have it at 62.9% so there's a breakdown somewhere. If I listed the factors that could be good for increasing mash efficiency, what factors could I look at to increase brewhouse efficiency?
Title: Re: BH & Mash Efficiency: Not Consistent & Not Good - WHY?!
Post by: brewfun on October 21, 2019, 08:00:21 AM
What I gave was an example, not specific to your setup. Insert your kettle percentage with your mash efficiency to get the right number for you.

Increasing mash efficiency is the most important way to increase overall efficiency since the kettle geometry is set. Mash pH, milling, grain freshness, mash bed thickness and sparge rate all play an important part as a group. You'll see incremental improvements with each, but all five will provide the highest yield.

The mill gap you mentioned may be too wide. Most homebrew mills are knurled, which might mean the gap has to be tighter.

Title: Re: BH & Mash Efficiency: Not Consistent & Not Good - WHY?!
Post by: Oginme on October 21, 2019, 08:25:49 AM
As Brewfun stated, there are two main areas to look at to improve your Brew House Efficiency (BHE).  First is are you drawing as much from the mash as you can (mash/lauter efficiency).  The second is the losses post mash which draws sugar laden volume from your system.  I would recommend targeting one of these areas to work on first.

The easiest is where you are losing volume in your process post mash (most probably post boil), measure the volumes of all your losses (trub in the boil kettle, sample draws, losses in tubing or pumps) and see where the wort is being lost and where there are opportunities to save that wort for the fermenter.

Next is your mash efficiency.  The top 5 things you can do to improve mash efficiency are crush, crush, crush, crush, and crush.  One of the things to look at is how much uncrushed grain kernels make it through your mill.  Take a sample of the crushed grains by scooping through the grains to the bottom, shake well and then pour out 100 grams onto a cookie tray. Spread this grain sample out and remove any kernels which look to be intact.  Squeeze them gently to make sure they are not fractured internally and collect intact kernels separately.  Weigh the collection of intact kernels and it should be less than 2 or 3 grams.  Obviously the smaller the number the better.  It takes a lot of time and effort to get the water into the kernel and soluble starches out of the kernel if they are not crushed.

Alternatively, you can get some test sieves and measure the weight of grains that are captured on a 14 mesh.  Again, this number should be low as it represents not only uncrushed kernels, but also larger kernel pieces which will not allow for water penetration easily or efficiently.  This is a more expensive route to go, but is favored by many breweries because it is faster and easily tracked for troubleshooting.

While a credit card width gap may be fine for most systems and grain bills, I would recommend getting some feeler gauges and pushing that gap a little bit smaller.  Tighten it just a bit until you are scared that it will create too much flour.  As long as you do not get a stuck mash, you are fine.  If you do get a stuck mash, then back off just a little bit.  Your mash efficiency should improve substantially with a finer crush.  While you are at it, make sure there are no gaps for the grains to bypass the rollers.

After the crush, I would look at how fast you are draining the wort from your mash.  Draining too fast causes the bed to compact and channels to form so that not all the water is freely able to come out nor does any sparge water come into contact with all the grains to draw more sugars from them.

Next, your method of sparging should be examined.  If you are batch sparging, then make sure that you mix the sparge water in thoroughly before draining.  I found that letting it sit a bit longer also draws more sugars from the grains though the increase in gravity in the sparge water decreased dramatically after about 10 to 15 minutes of extraction.

If you are fly sparging, the rate at which you allow the flow to move through the grain bed controls how well you extract the sugars still trapped in the grain.  Slower drainage, as with the initial runnings will prevent the grain bed from compacting and channeling to occur.  You really want to float the grains as a loose bed when fly sparging to make sure that all grain pieces see the water as it drains through the bed.

Lastly, how much volume of wort are you leaving in the mash tun?  Are there some improvements which can be made to minimize this volume? 

Once you make a change which has a meaningful improvement in your mash efficiency, stop and make sure you can repeat it a few times.  If the mash/lauter efficiency is variable, you will not have the control needed to make consistent batches of beer. 
Title: Re: BH & Mash Efficiency: Not Consistent & Not Good - WHY?!
Post by: Brew Bama on October 22, 2019, 02:52:58 PM
Oginme, that is probably the most detailed reply to the efficiency question I?ve seen over the years. Well said.

I would like to emphasize a point Oginme made: once you?ve made your adjustments, mash the same grist for several beers tracking SG and pH at 20 min intervals or so. Compare these data points to determine consistency. You should be very close brewday to brewday given the same processes and techniques. If a difference grain bill, process, and technique is used every time you fire up the brewery you have no idea if you?re consistent or not.

I dialed in my system over a Summer?s worth of Pale Ales this way (using different hops for variety) and I?ll never regret the confidence the experience has provided.
Title: Re: BH & Mash Efficiency: Not Consistent & Not Good - WHY?!
Post by: Eric19312 on November 15, 2019, 03:07:16 PM
That Robobrew is a recirculating system and might not want too tight of a crush.  I agree with previous posters that you want to think about mash efficiency and brew house efficiency separately.  Mash efficiency is the percentage of potential sugar from your grain bill that makes it to the boil.  Brewhouse efficiency is the percentage of potential sugar from your original grain bill that makes it into the fermentor.  The difference between these two numbers is the percentage of potential sugars that you got out of the grain and into the kettle but didnt get from the kettle to the fermentor.  If you leave a bunch of trub and hops in your kettle in order to get cleaner wort into your fermentor you are going to take a hit on brewhouse efficiency.  Thats a perfectly ok strategy and entirely your call as the brewer.  I like to design my recipes to permit me to leave a fair amount of junk in the kettle, that works on my system I am not sure how well that would work on Robobrew.  If you are basically dumping the entire kettle into your fermentor your mash efficiency should be almost exactly the same as your brewhouse efficiency.

Mash efficiency is a combination of two factors - conversion efficiency and lauter efficiency.  Conversion efficiency is a measure of how much of the potential sugar is realized in the mash.  You should aim for 100% conversion.  In brewing texts you will see advice about doing iodine test to make sure you have full conversion and to continue mash until it is done.  A finer crush will help speed conversion to a point.  Smaller particles get the water to the starch faster and easier.  But you do have a recirculating brewing system and too fine will create problems in the grain bed leading to either a stuck grain bed or channelling that defeats the purpose of the finer crush.  Personally I think your credit card measurement is pretty reasonable.  I'd like to see you testing your mash for full conversion before moving on to lautering/sparging.  I don't like the iodine test because it only is good at showing you if the starches that are mobilized into the wort have been converted.  Those starches aren't really your problem it is the starches that are still stuck in the grain that maybe haven't been mobilized/liquified yet.  The better way to check for full conversion is described here:
This is very easy to do with knowledge of your recipe and a refractometer.  Basically you calculate how much sugar will be in your wort when you reach 100% conversion, and then you start testing your mash at say 45 minutes and then again every 15 minutes until you reach that value (or stop at 90 min or 2 hours up to you).

Once your conversion efficiency is at about 100% you can work on your lauter efficiency.  I think this will be fixed in the robobrew system, in typical 3 vessel fly sparge brewing you will usually seek to adjust flow rate to optimize this value looking for a 45-60 min lauter/sparge, with BIAB you might incorporate a dunk sparge or squeeze the bag.  These are all designed to extract as much of the sugar as possible from the grain bed.

Anyway good luck - I do hear your frustration as I'd thnk one thing an all in one should be good at is repeatability.  Having your efficiencies come in all over the place just doesn't seem right.  I'd recommend reading that entire posting from braukaiser I linked above.